The synthesis of enantiomerically pure modified proline derivatives was achieved by using spiro beta-lactams as starting material that were prepared in turn by the [2+2]-cycloaddition of unsymmetrical cyclic ketenes with optically active imines. A theoretical study of the [2+2]-cycloaddition reaction, using density-functional methods, gave insights on the origin of the observed stereoselectivity of the Staudinger reaction. The spiro beta-lactams were transformed in the N-Boc derivatives and subjected to nucleophilic ring opening, affording the corresponding enantiomerically pure modified proline derivatives, isolated as orthogonally protected compounds.
[2+2]Cycloaddition reactions of imines with cyclic ketenes: synthesis of 1,3-thiazolidine-derived spiro-beta-lactams and their transformations / G. Cremonesi, P. Dalla Croce, C. La Rosa. - In: HELVETICA CHIMICA ACTA. - ISSN 0018-019X. - 88:6(2005), pp. 1580-1588.
|Titolo:||[2+2]Cycloaddition reactions of imines with cyclic ketenes: synthesis of 1,3-thiazolidine-derived spiro-beta-lactams and their transformations|
CREMONESI, GIUSEPPE (Primo)
DALLA CROCE, PIERO (Secondo)
LA ROSA, CONCETTA (Ultimo)
|Settore Scientifico Disciplinare:||Settore CHIM/06 - Chimica Organica|
|Data di pubblicazione:||2005|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1002/hlca.200590125|
|Appare nelle tipologie:||01 - Articolo su periodico|